Given the development of various satellite-based technologies, such as, global positioning systems (GPSs), and global-navigation-satellite-systems (GNSS), outdoor navigation systems have become very popular and incorporated in a variety of consumer products. Indeed, many portable electronic devices exploit such technologies to determine their own location and assist in directional guidance.
Recently, there has been considerable interest in indoor navigation and directional guidance. However, satellite-based systems are not as dependable for indoor applications, as indoor environments contain structural features that may compromise the effective reception of satellite signals.
To this end, electronic devices sometimes employ inertial navigation technologies to determine their location while in indoor environments. Such technologies may include one or more inertial navigation sensors and magnetometer sensors which, in combination, provide position, velocity, acceleration, and directional heading information. For example, such technologies may incorporate movement sensors (e.g., accelerometers) that detect movement of the devices and provide movement-related information, such as, velocity and/or acceleration; incorporate orientation sensors (e.g., gyroscopes) that provide information relating to the orientation of the devices; and incorporate directional sensors (e.g., magnetometers and/or compasses) that provide heading direction information.
Such technologies may then apply the sensor information to a variety of position estimation techniques, such as, for example, Pedestrian-Dead-Reckoning (PDR) estimation techniques, to approximate or establish a current position by taking into account previous position, direction, and travel distance information.